OAA (Outs Above Average) is Statcast's modern fielding metric, measuring how many outs a fielder records above (or below) what an average fielder would record on the same opportunities. Elite team OAA is +30 runs over a season; poor is -30.
OAA uses Statcast tracking to estimate the probability a play is converted to an out based on the starting position of the fielder, the speed and angle of the batted ball, and the difficulty of the play. Each play has an expected out probability. Actual out vs. expected = the fielder's contribution.
For individual fielders, OAA tells you how many extra outs they record per opportunity. Aggregated to a team, it tells you whether the defense is helping or hurting the pitcher.
Individual fielder (per season):
Team aggregate (per season):
Strong defenses convert more would-be hits into outs, which suppresses opposing team BABIP and ERA. The market often prices pitcher stats (ERA, FIP) without adjusting for defense behind them. A 4.20 ERA pitcher backed by a +30 OAA defense is sharper than a 4.20 ERA pitcher backed by a -20 OAA defense.
For betting:
OAA is Statcast-derived (camera-tracked starting positions, exit velocity, launch angle). DRS (Defensive Runs Saved) and UZR (Ultimate Zone Rating) are older metrics that use observational data with less precision. OAA is generally more accurate at the player level.
Team OAA (aggregated across positions, weighted by position importance) is one of 35+ inputs. It enters as a pitcher-quality modifier: a starter facing a team with strong infield OAA gets a small ERA adjustment downward (their balls in play become outs more often than the baseline), and vice versa. The effect is real but small, about 0.10-0.20 runs of expected scoring difference per game.
Theory is one thing — using the concept on tonight's slate is the value. These hubs are the practical application: